#include<iostream>
using namespace std;

int main(void)
{
    int p1=1;  // int var
    int *p2;  // int pointer
    p2 = &p1; // p2 point to p1
    cout<<p1<<' '<<*p2<<endl;

    p1 = 2;
    cout<<p1<<' '<<*p2<<endl;

    *p2 = 3;
    cout<<p1<<' '<<*p2<<endl;

    return 0;
}